The lucid yoldia is an inhabitant of moderately deep water 

 occupying depths which range between 28 and 2,943 m 

 (Clarke 1962). 



The samples in the NEFC collection are from waters which 

 range in depth between 10 and 366 m with a mean of 167 m. 

 The occupation of moderately deep water by this species is 

 reflected in the depth range distribution of the samples in the 

 NEFC collection in that 45% of the samples and 48% of the 

 specimens are in the 100-199 m depth range grouping; the 

 200-499 m grouping contains 33% of the samples and 40% of 

 the specimens, while the 50-99 m grouping contains 19% for 

 samples and 11% of the specimens; one sample (4%) and one 

 specimen (0.6%) are in the 0-24 m grouping (Table 54). 



The majority of our samples (40%) occurred in clay sedi- 

 ments; however, the greatest number of specimens (45%) 

 occurred in till sediments which contained 16% of the sam- 

 ples, clay on the other hand contained 16% of the specimens; 

 silty sand sediments contained 24% of the samples and 26% of 

 the specimens. Other sediment types in which this species 

 was found in our region were gravel, sand-gravel, sand-shell, 

 sand, and silt substrates (Table 55). There are 2 samples 

 containing 29 specimens which are unclassified with regard to 

 sediment type. 



Portlandia minuscula (Verrill and Bush 1897). Figure 95. 



Johnson (1934), Clarke (1962), and Abbott (1974) reported 

 the distribution of this species to extend from off Mas- 

 sachusetts to Virginia. 



The NEFC collection contains two specimens from one 

 sample of this rather rare bivalve species (Table 5). 



Our sample is from the Gulf of Maine proper adjacent to the 

 northern edge of Georges Bank (Fig. 95; Theroux and Wigley 

 footnote 4, table 167). 



The above authors gave the depth distribution of this spe- 

 cies as being 924 to 2,361 m. 



Our sample is from a water depth of 192 m which places it in 

 the 100-199 m depth range grouping. 



The sample from which the specimens of this species were 

 obtained was unclassified with regard to sediment type. 



Subclass CRYPTODONTA 

 Order SOLEMYOIDA 

 Family SOLEMYACIDAE 

 Genus Solemya Lamarck 1818 



Solemya borealis Totten 1834. Boreal awning clam. Figure 99. 



The boreal awning clam is normally found in the Canadian 

 Maritime Provinces of Newfoundland, Labrador, and Nova 

 Scotia and ranges south to the shores of Connecticut (Johnson 

 1934; LaRocque 1953; Ockelmann 1958; Abbott 1968, 1974; 

 Morris 1973; Emerson et al. 1976). 



Although Solemya borealis is a moderately common to 

 frequently occurring form within its range, the NEFC Speci- 

 men Reference Collection contains only one specimen from 

 one sample (Table 5). 



Our sample comes from the shore of Martha's Vineyard, 

 Mass. (Fig. 99; Theroux and Wigley footnote 4, table 177). 



Gosner (1971) reported this species from the Boreal pro- 

 vince, while Dance (1974) claimed that is a Transatlantic 

 inhabitant. 



The normal depth range for this species occurs in shallow 

 waters; however, it does range from 6 to 183 m in depth 

 (Abbott 1968, 1974; Gosner 1971). 



Our sample is from the shore at m depth which places it in 

 the 0-24 m depth range grouping. 



We have not found any sediment preferences in the litera- 

 ture and unfortunately the collection data did not contain any 

 sediment information for our sample. 



Solemya velum Say 1822. Common Atlantic awning clam. Fig- 

 ure 100. 



The range of this species is from Nova Scotia and New- 

 foundland to Florida (Johnson 1934; La Rocque 1953; Ockel- 

 mann 1958; Abbott 1968, 1974; Emerson et al. 1976). 



Solemya velum is common to frequently occurring and is 

 represented in our collection by 67 specimens from 33 sam- 

 ples (Table 5). 



Our samples are from the Gulf of Maine, the periphery of 

 Cape Cod, Mass., Georges Bank, and range on the outer 

 continental shelf and slope, south to slightly north of Miami. 

 Fla. (Fig. 100; Theroux and Wigley footnote 4, table 178). 



This species is an inhabitant of the Boreal, Virginian, and 

 Carolinian provinces (Coomans 1 962 ) ; Gosner ( 1 97 1 ) placed it 

 in the Boreal and Virginian , and Dance ( 1 974) stated that it is a 

 Transatlantic inhabitant. 



This species is normally found in intertidal areas and in 

 shallow water bays but it does range out to 90 m (Abbott 1968, 

 1974; Porter 1974; Emerson et al. 1976). 



The depth range of our samples is from 1 to 1,660 m with a 

 mean of 105 m. The 0-24 m depth range grouping contains 42% 

 of the samples and 65% of the specimens, while the 25-49 m 

 grouping contains 15% of the samples and 8% of the spe- 

 cimens; the 50-99 m grouping contains 27% of the samples and 

 20% of the specimens, while the 100-199 m and the 200-499 m 

 groupings each contain 6% of the samples and 3% of the 

 specimens; the 1.000-1.999 m grouping contains 3% of the 

 samples and 2% of the specimens (Table 56). 



Morris (1951), Abbott (1974), and Emerson et al. (1976) all 

 considered this species to inhabit mud and sand substrates. 



Our samples also occupied medium to fine-grained sub- 

 strates. Sand-shell substrates contained 10% of the samples 

 and 5% of the specimens; sand substrates 57% of the samples 

 and 35% of the specimens; silty sand sediments contained 

 14% of the former and 49% of the latter, while silt and clay 

 substrates each contained 10% of the samples and 5% of the 

 specimens (Table 57). There are 12 samples containing 28 

 specimens which are unclassified with regard to sediment 

 type- 



Subclass PTERIOMORPHIA 

 Order ARCOIDA 

 Family ARCIDAE 



Our collection contains 7 samples yielding 15 specimens of 

 members of the family Arcidae (Table 5). 



The distribution of our samples is split into two groupings: 

 one involves three samples in Chesapeake Bay, and the other, 

 more loosely distributed off the middle and southern New 

 England coast (Fig. 7; Theroux and Wigley footnote 4. table 

 11). 



11 



